1. Field of the Invention
The present invention pertains to refrigerators having freezer and fresh food compartments which are separated by a partition and, particularly, to a temperature sensor for signaling freezer compartment temperatures to a temperature control unit. More specifically, the invention is directed to the positioning of the temperature sensor within a special compartment of an air flow control member used in directing cooling air to flow from the freezer compartment to the fresh food compartment.
2. Discussion of the Prior Art
In typical household refrigerators having partitioned freezer and fresh food compartments, air is generally circulated over an evaporator and then delivered to both the freezer compartment and the fresh food compartment. One or more user operated temperature controllers are provided in order to manually adjust the desired temperature ranges for the two compartments. In certain know prior art arrangements, the fresh food control is operatively connected to a thermostat unit which receives fresh food compartment temperature signals by means of a capillary tube or other type of sensor mounted within the fresh food compartment. With such a system, the fresh food control thermostatically maintains the fresh food compartment temperature by periodically energizing and de-energizing a compressor of a refrigeration circuit.
In such a known arrangement, it is also common to connect the freezer control to an air flow damper positioned in a passageway through which air is delivered from the freezer compartment to the fresh food compartment. As the freezer control is set to a cold position, the damper is manually moved to allow less air into the fresh food compartment and the fresh food control responds by increasing the active time of the compressor to maintain the temperature of the fresh food compartment while further cooling the freezer compartment. Conversely, if the freezer control is set to a less cold position, the damper moves to allow more air to be sent from the freezer compartment to the fresh food compartment and, correspondingly, the fresh food compartment control compensates by running the compressor less often.
A major disadvantage of this type of known refrigerator temperature control system is that the temperature of the freezer compartment is only indirectly controlled based on the temperature in the fresh food compartment. One proposed solution to this problem is to incorporate separate temperature sensors for the fresh food and freezer compartments respectively. More specifically, a first sensor would be routed from either a thermostat or a damper in the temperature control unit to a desired location in the fresh food compartment, while a second sensor is routed from the other of the thermostat or the damper in the control unit to the freezer compartment. Temperature signals from the second sensor would then be used to regulate the refrigeration cycling directly or to automatically set the position of the air flow damper such that a direct control response can be obtained.
In these types of refrigerator temperature control systems, positioning of the sensor can be crucial to the operation of the overall system. The known prior art has had limited success in maintaining a consistent positioning of the sensor and has generally placed the sensor directly in the air flow stream to the fresh food compartment. The positioning of the sensor in this manner can result in rather large temperature fluctuations depending upon the rate of flow of cooling air across the sensor. In addition, condensation and conduction to the portion of the sensor in the freezer compartment can also have an adverse impact on the accuracy of the temperature readings.
Based on the above, there exists a need in the art of refrigerators for an improved temperature control system which can accurately and directly respond to temperature variations in a refrigerator freezer compartment. More specifically, there exists the need for an improved freezer temperature sensing arrangement for use in a temperature control unit of a refrigerator.